Editing Hyperfocal distance (section)

===Sutton and Dawson 1867===
Thomas Sutton and George Dawson define ''focal range'' for what we now call ''hyperfocal distance'':<ref name=":0" />

{{blockquote|Focal Range.  In every lens there is, corresponding to a given apertal ratio (that is, the ratio of the diameter of the stop to the focal length), a certain distance of a near object from it, between which and infinity all objects are in equally good focus. For instance, in a single view lens of 6 inch focus, with a 1/4 in. stop (apertal ratio one-twenty-fourth), all objects situated at distances lying between 20 feet from the lens and an infinite distance from it (a fixed star, for instance) are in equally good focus. Twenty feet is therefore called the "focal range" of the lens when this stop is used. The focal range is consequently the distance of the nearest object, which will be in good focus when the ground glass is adjusted for an extremely distant object. In the same lens, the focal range will depend upon the size of the diaphragm used, while in different lenses having the same apertal ratio the focal ranges will be greater as the focal length of the lens is increased.

The terms 'apertal ratio' and 'focal range' have not come into general use, but it is very desirable that they should, in order to prevent ambiguity and circumlocution when treating of the properties of photographic lenses. 'Focal range' is a good term, because it expresses the range within which it is necessary to adjust the focus of the lens to objects at different distances from it – in other words, the range within which focusing becomes necessary.}}

Their focal range is about 1000 times their aperture diameter, so it makes sense as a hyperfocal distance with CoC value of {{f/|1000}}, or image format diagonal times 1/1000 assuming the lens is a "normal" lens.  What is not clear, however, is whether the focal range they cite was computed, or empirical.